Inserter and splicer with register control for a reprinted web



May 5, 1970 c. A. L Ewls. JR., ETAL 3,510,036

INSERTER AND SPLICER WITH'REGISTER CONTROL FOR A REPRINTED WEB FiledMarch 29, 1968 3 Sheets-Sheet 1 o o a: #um

...mx 50 O O .mw zorruumoo mmrrmw MMSM www N ER am m um cw ND ATTORNEYSMay 5, 1970 c. A. LEWIS, JR., ETAL 3,510,036

INSERTER AND SPLICER WITH REGISTER CONTROL FOR A REPRINTED WEB 3Sheets-Sheet 2 Filed March 29, 1968 Ob OPOE E OO NO L c A. LEWIS, JR.,ETAL 3,510,036

3 Sheets-Sheet 5 May 5,1970

INSERTER AND sPLIcER WITH REGISTER CONTROL Fon A REPRINTED WEB FiledMarch 29, 1968 ATTORNEYS United States Patent O ABSTRACT F THEDISCLGSURE A preprinted web is scanned to detect a registration errorrelative to a further operation on the web, and the tension is raised orlowered to maintain registration. The actual web tension is continuouslyand directly measured by strain gauge means, and is limited to a highlimit to prevent breaking the web, and to a low limit which preventswandering of the web. The web tension is automatically reduced to thelower limit during automatic splicing, and until the splice leaves thesystem where it is under tension. A tab of retroreflective tape isadhered to `one end of the new preprinted roll in a desired locationrelative to the preprint on the new web, and the end of the roll isscanned by means of a retroreective scanner, which overcomesdifficulties caused when attempting to use an ordinary mark and scanner.

Publications, typically newspapers, often use a preprinted quality web,usually in color, which is inserted into the newspaper 4being printed.The other sheets are being printed in black and white by means ofprinting couples driven in unison from a common drive shaft. The back ofthe preprinted sheet may be printed in black and white as part of thenewspaper printing operation, and even the front of the sheet may havelocal information added thereto, for example the name and addressapplicable locally to advertisements `on the color preprinted sheet.This requires registration, and it is already known to maintain suchregistration by varying the tension applied to the preprinted web,thereby slightly varying the repeat length. However, if an errorcorrection is made too rapidly by excessive increase in tension, the webmay be broken, and on the other hand, if a correction requiring decreaseof tension is made too rapidly, there may be a loss of control ofside-to-side registration, frequently termed wandering of the web.

Another problem is to maintain maximum production by splicing with atight web or on the ily, instead of stopping the press to splice byhand. Apparatus for such splicing is known, but a major difficulty isthat the splice is a point of weakness which tends to break under theweb tension provided for registration control.

Thus, to maintain registration by varying web tension, leads to webbreakage at one extreme, and wandering at the other, and has preventedsuccess in automatically splicing with a continuously running tensionedweb, the freshly made splice being weaker than the web itself.

Summary of the invention As before, the web is scanned to detect aregistration error, and the tension on the preprinted web is raised3,510,036 Patented May 5, 1970 ice or lowered to so increase or decreasethe repeat length as to maintain registration. In accordance with theinvention, the actual web tension is continuously and directly measuredby strain gauge means, and an increase in web tension is limited to apredetermined desired high limit which is less than that which wouldbreak the web. Conversely a decrease in web tension is limited to apredetermined desired low limit which is high enough to preventwandering of the web. The web tension may be varied by means of brake ora vacuum box or tension straps, but in preferred form the web is fedbetween a metal draw roll and a rubber roll, because that does not maror scuft the printed matter; is independent of the reel stand orturnover stand tension; is more accurate and stable during registerchanges; and the feed is independent of the printing couples which, forletterpress and olfset press, have gaps between plates on the platecylinder. The draw roll is driven by the main drive shaft at a speedapproximating the desired web speed, and a slight servo motor correctionis fed into the drive through a 360 degree continuous running registerof the differential or planetary gear type, thereby varying the speed ofthe draw roll to provide a desired web tension which is held between thepredetermined lower and upper limits of web tension.

The web tension for newsprint may range normally from say 11/2 to 3pounds per linear inch of web width, but the lower limit may be as lowas say 1/2 pound per linear inch. In accordance With a further featureof the present invention, the web tension is automatically reduced tothe lower limit during the splicing operation, and until the spliceleaves the system so that it is no longer under breaking tension. Thereis a delay means the running out of which restores normal web tensionbetween the aforesaid limit values and as needed for registration. Thedelay may be enough for the preprinted web to be collated with otherwebs being printed and to reach the folder and cutter.

With a preprinted web the splicing operation must secure registration ofthe preprint on the expiring and new webs. A tab of retroreflective tapeis adhered to one end of the new roll in a desired location relative tothe preprint. The roll is later brought up to approximate 'web speed,and the end of the roll is scanned by means of a retroreilectivescanner. This is found to give a strong signal without backgroundinterference, and it overcomes diculties which have arisen whenattempting to use an ordinary mark scanned by an ordinary scanner,because the end of the paper roll is not a precision surface with xedlocation.

The foregoing and additional features of the invention are described inthe following detailed specication, which is accompanied by drawings inwhich:

FIG. l is a schematic diagram showing apparatus for additional printingon both sides of a preprinted web;

FIG. 2 is an electrical diagram applicable to the apparatus shown inFIG. 1;

FIG. 3 is a perspective view of a preprinted roll;

FIG. 3A shows the same prepared for automatic spliclng;

FIG. 4 is a pulse diagram explanatory of the operation of the splicingapparatus;

FIG. 5 is a schematic electrical diagram showing the circuitry of thesplicing apparatus; and

FIG. 6 is explanatory of the retroreflective scanner.

Referring to IFIG. 1, the preprinted web roll is shown at 12 and the webdrawn therefrom passes around rollers 14 and 16 to a metal draw roll 18,which is driven nearly in synchronism with the printing couples. The webis squeezed between draw roll 18 and a rubber roll 20 for accurate feedof the web. The pressure may be obtained by means of air cylinders,controlled by a solenoid valve 21. The web then passes around a roll 22to a guide roll 24 leading to a first printing couple, which in thepresent case comprises a plate cylinder 26 and a blanket cylinder 28.

The web then runs to another printing couple for printing the oppositeside of the web, this comprising a plate cylinder 30 and a blanketcylinder 32. As here shown these printing couples are of the letterpress type, and print in black and white, the preprint being in color.

The web then runs over guide rollers 34, 36, 38 and 40. It may becombined or collated with additional webs supplied at 42, and themultiple webs may pass around a guide roller 44 leading to folding andcutting mechanism schematically suggested at 46, where the newspapersare completed. For magazine presses the product may be called signaturesThe printing couples 26, 28, 30 and 32 may be geared together and aredriven in unison with printing couples for additional webs by means of amain drive shaft a fragment of which is indicated at 50. This driveshaft is mechanically connected to the printing couples, and it alsodrives the draw roll 18 but with provision for a slight speedcorrection. The drive for this purpose is through a chain or timing belt52 leading to a 360` degree continuous running register of knownplanetary gear (also called differential gear) type shown at 54. In theparticular apparatus here illustrated it was not convenient tomechanically connect the output shaft 56 of the gear box 54 directly tothe draw roll 18, and it therefore is applied to a Selsyn master unit 58electrically connected by cable 60 to a Selsyn slave motor 62, geared at64 to the draw roll 18. An additional cable is shown at 66 connected toa Selsyn phasing unit 68 for applying power to the Selsyn units. Thispart of the apparatus may be conventional, and the net result is asthough the output shaft 56 of differential gear box 54 were geareddirectly to the draw roll 18.

An error in registration is determined by means of a web scanner 74, anda phase micrometer 76 is here shown connected to the shaft of the platecylinder 30, but it might equally well be connected to the shaft of oneof the other cylinders or to the main drive shaft. The signal from webscanner 74 is supplied through conductor 78 to computer circuitry in acontrol panel indicated at 80. The scanner 74, phase micrometer 76, andcomputer circuitry may be one of the types sold by the RegistronDivision of Bobst Champlain, Inc., located at Roseland, N. J., andidentified as Registron models C-372, C-350, and R500. The signal fromphase micrometer 76 is supplied through conductor 82 to the circuitry at80, and the resulting error correction signal from the computer issupplied through cable 84 to the correction motor 70.

In accordance with the present example, the actual web tension ismeasured by means of strain gauge transducers. Such a transducer isschematically represented at 86 and is connected by cable 88 to thecomputer circuitry at panel 80. Another such transducer is located atthe other end of roll 22, and is connected into the circuitry by cable90. In practice there are preferably four transducers connected inbridge form, as described later.

Referring now to FIG. 2 of the drawing, the scanner 74 and phasemicrometer 76 are shown connected to computer circuitry at 92 to deliveran error signal at 94. The correction motor is shown at 70, and in thepresent case is a DC motor controlled through silicon 4 controlledrectifiers in much the same manner as is described in Pat. No.3,355,640, issued Nov. 28, 1967, and entitled Bidirectional ElectricalServo System.

The circuitry shown in box 92 may be one of the Registron Models C-350,C-372 or R-500 previously mentioned. The proportional error signaldelivered at 94 may be plus or minus. It is here utilized withintegration circuitry much like that described more fully in a copendingapplication Ser. No. 599,929, filed Dec. 7, 1966, and entitled WebControl Systems with Integrator. The proportional error signal isintegrated at 96 and the integrated error signal is supplied to asumming amplifier 98. This is a miniaturized integrated circuitsometimes called an operational amplifier, an example of which is theModel 709 made by Fairchild Semiconductor of Mountain View, Calif., aDivision of Fairchild Camera and Instrument Corporation.

The proportional error signal is supplied on the conductor 100 to thesumming amplifier 98, and the summation of these twosignals (meaning theoriginal proportional error signal and the integrated error signal)appears at 102. Resistor 104 serves merely to change the voltage signalto a current. Switch 106 is normally closed and the signal at 184 isused to control the correction motor 70. This is a DC motor, and itsarmature is energized from an ordinary AC power supply (usually sixtycycles) indicated in the upper right-hand corner of the diagram as 110volt AC. The supply is under the control of either silicon controlledrectifier 108 or 110, to supply rectified power to the motor 70 in onepolarity or the other. The motor receives only the alternate half waves,these being either the positive half waves, or the negative half waves.Toaccomplish this there is a slave frequency doubler or synchronousdouble frequency pulse source indicated at 112, and the cycle pulse isled to AND gates represented by transistors 114 and 118.

The signal from the summing amplifier 98 is supplied to transistors 122and 124, one being of the NPN type, and the -other being of the PNPtype, so that one conducts for one polarity signal, and the otherconducts for the opposite polarity signal. The output of transistor 122goes to transistor 114 which makes the signal digital or on-andoff incharacter, and the output of transistor 114 goes to transistor 116 whichserves as a power transistor. It supplies transformer T1 which isconnected to the gate of silicon controlled rectifier 108.

If the polarity of the signal from the summing amplifier 98 is ofopposite polarity or negative, it provides an output from transistor124, which is supplied through a transistor 126 to transistor 118, whichacts as an AND gate and corresponds in function to transistor 114. Thetransistor 126 is interposed in this case in order to change fromnegative to positive polarity. The signal from transistor 118 drivespower transistor 120 which through transformer T2 controls the supply ofthe double frequency from the source 112 to the gate of the siliconcontrolled rectifier 110, and so controls the supply of power half wavesfrom the power source to the armature of the servo motor 70.

It should be noted that there is a rate feedback loop at 128. Capacitor129 acts as a bypass or filter capacitor. Thus there is a DC feedbackfrom motor 70 applied to the correction signal, and the effect of thismay be varied by a resistor 130. 'I'he feedback is from the armature ofmotor 70, and helps make the control linear in character.

With this arrangement the double frequency pulse is applied to the gateof one silicon controlled rectifier or the other in order to supply atrain of substantially full width alternate and therefore unidirectionalhalf waves, to drive the motor 70. The feedback loop 128 results in amotor speed which is proportional to the magnitude of the error, andregardless of the torque load.

The servo correction motor 70 turns the cage of the differential gearbox(54 in FIG. 1). The motor is linear,

and turns in only one direction. It turns rapidly for retard, and slowlyin the same direction for advancef (Retard requires increased webtension to increase the repeat length, and vice versa for advance.) Thespeed of the motor is dependent on the tension required to holdregistration, and also on the speed of the press as described later. Themotor is pulsed through the silicon controlled rectifiers duringalternate 1/2 waves of the AC supply, 'and the back of the motor iscompared to the correction voltage at 102 during the non-energized 1/2waves of the AC supply. In this manner, the motor is utilized as a powerdevice, while serving also as a generator which feeds back a signalrepresenting the armature speed. When the armature feed back on line 128equals the correction voltage at point 102, the silicon controlledrectifiers are pulsed only when necessary to maintain proper speed.

As so far described, the system is generally like that described in thecopending application Ser. No. 599,929, with particular reference to itsFIG. 12. This applies here to the upper half of FIG. 2, while circuitryfor the present improvement limiting the range of variation of webtension is shown in the lower half of FIG. 2. We provide a roller 18fitted with strain gauges or tension transducers marked 86. Theparticular transducers here used are roll bearing supports manufacturedby Kidder Press Co., Inc., of Dover, N.H. The supports are secured in afixed frame, and include two strain gauges in the bearing support ateach end of the roll, one acting in compression and the other intension, and these four are connected in bridge form as shown by theresistance bridge `86 at the lower left portion of FIG. 2. The roller 18is schematically represented above the bridge 86.

In the system here illustrated the servo motor 70 preferably runs in onedirection, but electrically the system is the same as a bidirectionalsystem, because the electrical supply is fed in either direction, andwhen fed in the reverse direction, it provides for a rapid slowdown ofthe motor when going from a higher speed to a lower speed. In otherwords, the power flow is bidirectional, and in the slowdown periods, themotor acts as a generator which feeds power to the line, but this feedis through the other one of the two silicon controlled rectifiers 108and 110. (It is not the rate feedback on loop 128 which comes from theintermediate half cycles.)

The bridge 86 is energized from an AC 110 Volt supply shown at 132,which is stepped down to 6 volts by means of a -transformer 134, thesecondary of which has a center tap. The output of bridge l86 is afunction of the web tension, and provides a signal on two conductorsconnected to two summing resistors 136. A potentiometer 138 may bevaried for zero adjustment, to compensate for the weight of the roller18 and for tolerance in the components. It is connected through asumming resistor 139. The signals are combined at 140k and are suppliedto a summing amplifier 142 which again may be a Fairchild type 709operational amplifier. It is connected through resistor 144 as afeedback amplifier.

Because the web being handled may have widths of say 15, 30, 45 or `60inches, the total web tension differs proportionally in each case, andthis is taken care of by a switch 146 which selects one or another offour different resistors 148, depending on the web width, the smallerresistor corresponding to smaller web width. These resistors may bermade adjustable for preliminary adjustment, but then may be left fixedduring normal use of the apparatus. The resistors 148 are in thefeedback loop, and in combination with the resistor 144 they select theproper gain of the amplifier depending on the width of the web. Theoutput at 150 is an AC voltage which is proportional to pounds perlinear inch at the web.

This AC signal is changed to DC in a demodulator 152. The capacitance154 in combination with a resistor 156 acts as a filter. The DC signaloperates an ammeter 158 through a resistor 160, and this meterpreferably has a scale in terms of web tension in pounds per inch of webwidth.

This has a particular practical advantage in that the operator can readthe tension to which the web is being subjected to hold register, and ifthe tension remains consistently high, say 3 pounds or more per inch ofweb width, he can arrange to have the plate cylinder shaved to slightlyreduce its diameter, so that the normal web tension will be lowered to amore desirable figure of say 1'1/2 pounds per inch of web width. WithI'the web running at high tension, there is little range left availablefor a retard correction, and such a correction may take longer thanwould be necessary if the web were running at lower web tension. Thusthere would be more waste or discarded web when starting up.

For this purpose the meter preferably has a second scale paralleling thefirst scale, and showing the amount (in thousandths of an inch) theplate cylinder should be shaved to achieve an optimum tension level (say11/2 pounds per inch of web length for newsprint). If the web tensionruns consistently low, say 1/2 lb. per inch of web width, the platecylinder may be packed or shimmed to increase its effective diameter sothat the normal web tension will be raised to the more desirable levelof say 11/2 pounds per inch of Web width.

'Ihe lower tension limit is adjusted by means of a potentiometer 162,and the upper limit is adjusted by means of a potentiometer 164. Thereis a 12 volt supply at 166, through voltage dropping resistors 16S, andthe combination of resistor and potentiometer 162 acts as a voltagedivider.

An operational amplifier (c g. Fairchild Type 709) compares the voltageat 172 (representing the low voltage limit corresponding to the desiredlow tension limit) with the voltage at 174 which is proportional to theactual web tension in pounds per linear inch. When the voltage at 174 isgreater than the voltage at 172, the output of the amplifier 170 at 176is a negative voltage, typically minus 12 volts. The voltage on thediode 178 at 180 is clamped to ground at minus 0.6 volt, this being theforward breakdown voltage of silicon diode 178.

If however, the voltage at 174 is less than the voltage at 172, becausethe web tension is less than the desired low limit, the output voltageof the amplifier 170 at 176 is a positive voltage proportional to thedifference between the two input voltages. The voltage at point then ispositive and feeds through line 182 and summing resistor 183 to com-binewith the error voltage at 184. This positive voltage will drive theservo motor 70 slower to increase the web tension above the lower limit.

The resistor 186 is a feedback resistor which reduces the gain ofamplifier 170, so that the output at 176 is proportional to thedifference between the inputs. This is done so that the feedback actionis not too abrupt and does not cause hunting or unstable condition.

Coming now to the high limit part of the diagram, the amplifier 1188again is an operational amplifier (eg. Fairchild Type 709). Point 190 isat a potential representing the high tension limit, say four pounds perlinear inch. When the voltage at 174 representing actual web tension islower than that at 190, the amplifier output at 192 is positive, andtypically would be at the saturation voltage of the amplifier, say plus12 volts. However, the voltage at the point 194 is clamped at plus 0.6volt representing the forward breakdown voltage of the silicon diode196.

If the voltage at 174 representing the actual web tension exceeds thelimit voltage at 190, the output of the amplifier at point 192 goesnegative, thereby providing a negative voltage at the point 194, andthrough summing resistor 183, provides a negative voltage at the point184. This negative voltage is in proper direction to slow down the motor70, thereby reducing the web tension to a level approximately equal tothe high web tension limit as set at point 190.

The two resistors 198 are employed to prevent excessive current beingdrawn through the diodes 178 and 196 when the web tension is properlylocated between the low and high limits. The two resistors 200 are usedto isolate the two outputs applied to resistor 183 because it isimpossible to be at the low and high limit simultaneously.

When the web tension is -between the desired limits, the voltage atpoint 180 is minus 0.6 volt, and the voltage at the point 194 is plus0.6 volt. The output going to resistor 183 is therefore zero, theresistors 200 having the same value. The tension limits and thedescribed circuitry in the lower half of FIG. 2 therefore have no effecton the normal registration control of the motor 70, as long as the webtension is at a value between the predetermined low and high limits. Theweb tension is freely varied between the low and high limits as neededfor registry by the circuitry in the upper half of FIG. 2, withoutinterference from the circuitry in the lower half of FIG. 2.

With reference to FIG. l it will be recalled that the main drive of thedraw roll 18 is from the main drive shaft 50, and that the servo motor70 supplies only a slight correction. The amount of this correction (theservo motor correction) is preferably kept in proportion to the press orweb speed. Thus, if the press speed were doubled from say 500 feet perminute to 1000 feet per minute, the servo motor 70 should double itsspeed range in order to remain in proportion. Circuitry for this purposeis shown in the lower right-hand corner of FIG. 2.

Reverting to FIG. 2 there is a tachometer 202 which is driven by themain drive shaft. The output of tachometer 202 is in volts per thousandfeet of web speed per minute, and is applied to an operational amplifier204 (e.g. Fairchild Type 709). It is supplied through a resistor 206,and the output is connected to a lamp 208 which excites two cadmiumsulphide photoconductive resistors 210 and 212. These two resistors areso positioned relative to the lamp 208 that their values in ohms are alogarithmic function of the lamp excitation voltage.

The resistor 210 is energized from a minus l2 volt supply, and is summedto the plus input from the tachometer by the operational amplifier 204,as shown by the connection 214. The difference, if any, is amplified inthe amplifier 204, which acts as a high gain amplifier. The excitationof the lamp 208 is made logarithmic, and provides a linear relationshipbetween the photoconductive resistor 210 and the tachometer voltage. Thetwo photoconductive resistors 210 and 212 are selected to be alike, saywithin of each other, and therefore the resistor 212 remains within 5%of the resistor 210 throughout the entire web speed range as determinedby the tachometer 202.

The assembly of the lamp and photoconductive resistors shown in thebroken line rectangle 216 is a commercially available unit Model No.1033-2 manufactured by National Semiconductor, Inc. of Montreal, Canada.

Initially, when the printing press is just starting up and operating atlow speed, the resistance value of the resistor 212 is very highcompared to that of the resistor 131. As the press increases in speed,the resistor 212 decreases in value, thereby providing a smallerfeedback voltage from the armature of the servo motor 70 at the point218. The resistor 130 is much larger than the resistor 131. The voltageat 218 is summed through resistor 130 at point 184, and the voltagedifference from the correction voltage drives the silicon controlledrectifiers (one or the other). As the press speed increases the motor 70is allowed to run faster for the same feedback voltage at the point 184.The photoconductive resistor 212 and the resistor 131 act as a voltagedivider network at the point 218, which divider is approximately linearfor all press speeds above a very low initial press speed.

With automatic splicing, to be described later, the splicing operationconstitutes an abrupt change or departure from registration, and anadditional circuit refinement may be provided to accelerate the responseto that change.

For this purpose an operational amplifier 220 (e.g. Fairchild Type 709)and an integrator 222 may be added, but the use of these components isan optional refinement and is not essential. This combination providesat point 224 a signal which is proportional to the rate of change in theerror signal. The rate of change error signal is provided at 224 becausethe output of amplifier 220 is fed to the input of the integrator 222,and its output is fed back on line 228 to the amplifier 220. Thus arapidly changing error which occurs at the time of splicing, causes ahigher input voltage on line 226 to the summing amplifier 98.

Initially the error signal at 94 is transmitted directly through theamplifier 220 and arrives on line 226 as an input to the summingamplifier 98. A short time later the output of integrator 222 subtractsfrom the error signal at the input to amplifier 220. Some time later theoutput of the integrator 222 equals the voltage at the input toamplifier 220, thus providing zero effect at point 224. The timeconstant of the integrator 222 can be adjusted to provide the aforesaidunusually large correction for a short time duration, in order to morerapidly correct the registration error when splicing, so as not to havethe output of the main integrator 96 driven excessively far from itsnormal condition. The voltage on line 228 subtracts from the voltage online 94, and can never provide more than neutralization of voltage atthe input to amplifier 220, and therefore the effect of the addedcomponents 220 and 222I is eliminated after a brief time. Thereafter thenormal operation makes uses of only the integrator 96 and theoperational amplifier 98 as described in the aforesaid copendingapplication Ser. No. 599,929.

The splice of a new paper roll to an expiring roll may be performedmanually with shut down, but in preferred form the splice is madeautomatically at full web speed. For this purpose, the paper roll shownat 12 in FIG. l is mounted on any suitable turnover stand, and referringto FIG. 5, this is suggested by roll 12 which is an expiring roll, and anew roll 230, these being carired on turnover arms 232 rotated at 234.Turnover stands are well known and require no detailed description. Manyhave three arms apart, instead of two as here shown. Apparatus with twoarms is described for example in U.S. Pat. 3,195,827, issued July 20,1965, and entitled Splicer for Moving Web.

The splicing should provide registration of the print on the new web tothat on the expiring web, and this requires preparation of the new paperroll.

Referring to FIG. 3, the new roll 230 has a position arrow 236 which isextended by means of a line 238 for positioning in some types of reelstand. A register mark ahead of the line 238 is located as shown at 240.The end is trimmed to V shape as shown at 242, and adhered with anadhesive tab 244. A band 246 is marked to represent an area for contactwith a speed-up belt which brings the new roll up to web speed beforesplicing is attempted.

A flexible steel marking gauge 248 is bent around the roll from the line2-40 and corresponds to a desired number of repeat lengths of thepreprint material, say three repeat lengths, thus arriving at the mark250 in FIG. 3A. A tab of reflective tape is applied to the end of theroll as shown at 252. It is preferably a commercially availableretroreflective tape, an example being that made by Minnesota Mining andManufacturing, Inc. (or 3M) of St. Paul, Minn., and identified as theirScotch Light Reflective Sheeting No. 3270, with pressure sensitiveadhesive back. Adhesive is applied to the outer end of the roll assuggested at 254, but the band 246 is left clear for the speedup belt.

Referring now to FIG. 5, the end of the roll 230 is scanned by aretrorefiective scanner 256, and responds to passage of theretroreflective tab 252. The resulting pulse is applied to an AND gate258.

At the same time the preprint on the expiring web 260 is scanned by aweb scanner 262. The web 260 is normalhl clear of the new roll 230, butmay be pressed against the new roll at the instant of splice, as bymeans of a brush 264 forming a part of the splicing apparatus. The saidapparatus also includes a knife 266 which operates after the splice iseffected. (The direction of rotation in FIG. is opposite the directionof rotation indicated in FIGS. 3 and 3A). The measure 248 (FIG. 3)provides delay for movement of the brush 264.

The signal from the web scanner 262 consists of a series of pulses, onefor each registration mark or repeat length, as indicated in the upperpart of FIG. 4 marked WEB SIGNALS. The pulses from the roll scanner 256are spaced much further apart, as indicated by the lower part of FIG. 4marked ROLL SIGNALS. Inasmuch as the number of repeat lengths on theroll circumference is ordinarily an odd amount, there will beregistration of the preprinted matter at intervals where the pulsescoincide, as indicated by the pulses 268 and 270 in FIG. 4.

The retroreflective arrangement is schematically indicated in FIG. 6.The light source is schematically shown at 272, and the light passesthrough a half silvered mirror 274 to a lens system 276 which projectslight against the end 278 of the new roll 230. The reflection from theretroreective tape is back through the same lens system 276 to the halfsilvered mirror 274, and excites a photocell 280. The retroreective tapereflects only light perpendicular to the end of the roll. Thisarrangement gives a strong signal without background interference,despite the somewhat irregular nature of the roll end, and the existenceof some wobble in spacing between the scanner and the roll end.

The width of the retroreflective tab 252 may be used as a measure oftolerance in the splicing operation. Thus, if the splice tolerance isplus or minus one inch, the tab is made two inches in width incircumferential direction.

When the operator sees the expiring roll 12 becoming small, and havingalready prepared the new roll for splicing, he presses a start buttonforming a part of the splicer apparatus, and not shown in FIG. 5. Insome cases this causes turnover at the reel stand until the new roll isin splicing position, at which time the speedup belt operatesautomatically. In other cases the turnover of the reel stand isseparately controlled, and the start button starts operation of thespeedup belt to bring the new roll up to web speed. In either case, whenthe expiring roll has nearly expired the operator presses a paster orsplice button, shown at 281 in FIG. 5, and this sets the output state ofthe flip-op or bistable element 282 at high level, and an output is ledthrough conductor 284 to the AND gate 258. The element 282 acts as aholding relay so that the button 281 does not have to be held down.

The pulses from the web scanner 262 are delayed in a delay circuit 286to compensate for the location of the web scanner 262, which is not atthe splicing point. It also has a ten turn potentiometer 288 for veryfine adjustment of the amount of time delay. The tachometer 202 (whichcorresponds to the tachometer 202 in FIG. 2) adjusts the time delay inunit 286 automatically, because the delay must be related to web speed,that is, it must be compensated for web speed in order to represent weblength rather than time delay.

As soon as there is a coincidence of pulses, as shown at 268, 270 inFIG. 4, corresponding to proper registration, there is a signal whichpasses through the AND gate 25,8 and the conductor 292, which actuates aoneshot multivibrator 294, which in turn energizes a relay 296 whichserves to actuate the splicing brush 264 previously mentioned.

The signal from one shot 294 is supplied through line 298 to anotherdelay circuit 300. This delay circuit is also compensated for web speed,as is indicated by the connection 302 to the tachometer 202. The delayin circuit 300 is much greater, and covers the web length all the wayfrom the splicing brush to the folder. This may be highly variable, sayanywhere from three to eight seconds, depending on the particularprinting press layout, and the distance of the folder from the splicingpoint. Adjustment of the delay is indicated by the variable resistor304, but this remains fixed once it has been adjusted for a particularprinting plant.

The relay 306 is energized, for the duration of the delay in 300, andreverting briefly to FIG. 2, this corresponds to opening of the switch106 which is the relay contacts. This would tend to stop the servo motor70, but because of the limit arrangement provided by the circuitry inthe lower half of FIG. 2, the servo motor drops to a speed correspondingto the low web tension limit. The motor 70 continues to run at thatspeed which reduces the web tension to the desired minimum of say 1/2pound per linear inch, and thereby guards against breaking the newlymade splice.

This requires a fast slowdown because the motor ordinarily would beapplying a tension above 11/2 pounds per inch, and the feed of reversepulses of power supply through the reverse silicon controlled rectifierhelps produce the desired fast slowdown.

Reverting to FIG. 5, the knife 266 is actuated a little later than thebrush 264, to make sure that the adhesive area is already pressedagainst the expiring web before the tail of the expiring web is cut off.This knife delay is obtained as a part of the usual and known splicingequipments.

The reduced web tension to protect the splice is maintained until thetime of delay circuit 300 runs out.

To reset the circuitry of FIG. 5, and more specifically the flip-flop282, an output pulse of the one shot 294 not only works the relay 296,but also sends a signal on a line 308 back to the reset terminal of theflip-flop 282.

The delay circuits in rectangles 286 and 300 need not be described indetail, because known delay circuits may be used.

The departure from registration caused by splicing is quickly rectified,say in fifty repeat lengths, and in newspaper work this is acceptable,there being no need to discard the newspapers in question. Moreover, theadjustment at 288 can be made to allow say one inch for the change inregister caused by the abrupt drop in web tension when splicing, causedby opening of contacts 106.

It will be understood that the operator later removes the expired rollwith its severed tail from the turnover arms. A new roll is added and isprepared as previously described in connection with FIGS. 3 and 3A. Itis shifted to splicing position. The operator starts the speed-up of thenew roll, or it may start automatically with turnover, and in due coursethe operator presses the paster button to initiate the splicing cycle.An actual splice takes place automatically as soon as the printed matteron the two webs are in registration. The turnover arms shown in FIG. 5are not drawn to scale, and in actual apparatus the arms may be rotatedwithout interference. In many stands there are three arms rather thantwo as here shown.

The present inserter controls the registration of a fully or partiallypreprinted web, to a printing unit or folder or any high-speed web-fedmachinery, by controlling the feed of the web through a set ofrubber-to-steel infeed draw rollers. The equipment may be used withletterpress, offset, or rotogravure, and is independent of the nature ofthe roll stand or tension system fitted to the particular press. Thepreprint used can be produced on one machine, and inset into the same oranother type of machine. For example, letterpress preprint can be insetinto letterpress machines to increase paging or to introducerun-of-press color; or alternatively, high quality color rolls can beproduced by offset, rotogravure or magazine letterpress, and inset intoletterpress, newspaper presses, or other web-fed machinery. Variousother combinations are possible. The web tension can be produced inother ways than by a draw roll, although that is preferred.

The use of a correction signal which combines both a proportional errorsignal and an integrated signal (provided by the components 96 and 98 inFIG. 2) has a number of advantages. The integrated signal is relativelylarge, and makes possible the use of a low gain and therefore stablesystem. rIhe proportional error signal decreases 4with correction, andso tends to offset the growth of the integrated signal, but the amountof decrease is slowed down, which helps avoid instability. Theintegrated signal alone is not sensitive to a sudden change, but theproportional error signal does respond. Because of the integrated signalthe error signal is driven to approach zero, because the integrationcontinues as long as an error signal is present. The integral channellooks like a high gain loop for errors which occur very gradually. Ithelps take care of a cumulative error, and when working with apreprinted web a repeat length variation is a cumulative error. Becauseof the difiiculty of introducing mechanical drives on a variety ofdifferent printing presses, a Selsyn drive is used between the gear boxand the draw roller, which gives flexibility for installation.

It is believed that the construction and operation of our improvedinserter and splicer for a preprinted web, as well as the advantagesthereof, will be apparent from the foregoing detailed description. Itwill also be apparent that lwhile we have shown and described theimprovement in preferred form, changes may be made without departingfrom the scope of the invention, as sought to be defined in thefollowing claims.

We claim:

1. In the operation of a system operating on a preprinted web, andproviding registration as to the preprinted matter, the method whichincludes scanning the web to detect a registration error, raising orlowering the tension on the preprinted web in response to detection ofan error to so increase or decrease the repeat length as to tend tomaintain registration, continuously measuring the resulting web tension,limiting any increase in resulting web tension to a predetermineddesired high limit which is less than that which may break the web, andlimiting any decrease in resulting web tension to a predetermineddesired low limit which is high enough to prevent wandering of the web.

2. A method as defined in claim 1, which includes feeding the webbetween a metal draw roll and a rubber roll, driving the draw roll at aspeed approximating the desired web speed, and feeding in a variablecorrection to slightly vary the speed of the draw roll to provide adesired web tension which is between the predetermined lower and upperlimits of web tension.

3. A method as defined in claim 2, which includes splicing a new web toan expiring web without stopping the expiring web, automaticallyreducing the web tension to the lower limit of web tension during thesplicing operation and until the splice leaves the system so that it isno longer under breaking tension, in order to prevent breaking at thesplice, and restoring normal web tension between the limit values asneeded for registration after the spice has moved out of the systemwhere it is under tension.

4. A method as defined in claim 3, which includes applying a tab ofretroreective tape to the end of the new roll in a desired locationrelative to the preprint on the new web, bringing the new roll up toapproximate web speed, and scanning the end of the new roll by means ofa retrorefiective scanner for purposes of securing registration of thepreprint on the expiring and new webs when splicing.

5. A method as defined in claim 4, which includes making the width ofthe retrorefiective tape correspond to the plus and minus tolerancedesired for the splicing operation.

6. A method as defined in claim 1, which includes splicing a new web toan expiring web without stopping the expiring web, automaticallyreducing the web tension to the lower limit of web tension during thesplicing operation and until the splice leaves the system so that 12 itis no longer under breaking tension, in order to prevent breaking at thesplice, and restoring normal web tension between the limit values asneeded for registration after the splice has moved out of the systemwhere it is under tension.

7. A method as defined in claim 1, which includes applying a tab ofretrorefiective tape to the end of the new roll in a desired locationrelative t0 the preprint on the new web, bringing the new roll up toapproximate web speed, and scanning the end of the new roll by means ofa retrorefiective scanner for purposes of securing registration of thepreprint on the expiring and new webs when splicing.

8. A method as defined in claim 7, which includes making the width ofthe retrorefiective tape correspond to the plus and minus tolerance`desired for the splicing operation.

9. A system for operating on a preprinted web in registration with thepreprinted matter on the web, said system comprising means for scanningthe web to detect an error in registration, web tension means responsiveto said scanning means for raising or lowering the tension on thepreprinted web to so increase or decrease the repeat length as tomaintain registration, transducer means to continuously measure theresulting web tension, and means effective to maintain the resultingtension below a predetermined upper limit and above a predeterminedlower limit while said web tension means raises or lowers theregistration tension of said web between said upper limit and said lowerlimit in response to the error sensed by said scanning means.

10. A system as defined in claim 9, in which the means to vary thetension on the preprinted web comprises a metal draw roll and a rubberroll between which the web is squeezed, means for driving the draw rollat a speed approximating the desired web speed, and means including acorrection motor and a 360 degree continuous running register of thedifferential -gear type for feeding in a variable speed correction toslightly vary the speed of the draw roll to provide a desired webtension which is between the predetermined lower and upper limits of webtension.

11. A system as defined in claim 9, in which there is means effective toset the upper limit of web tension at a value which is less than thatwhich would break the web, and means effective to set the lower limit ofweb tension at a value which is high enough to prevent wandering of theweb.

12. A system as defined in claim 11, which includes means for splicing anew web to an expiring web without stopping the expiring web, means toautomatically reduce the web tension to the lower limit of web tensionduring the splicing operation and until the splice leaves the system sothat it is no longer under breaking tension, and a delay means therunning out of which restores normal web tension between the limitvalues and as needed for registration.

13. A system as defined in claim 12, which includes a tab ofretroreflective tape adhered to one end of the new roll in a desiredlocation relative to the preprint on the outer end portion of the newweb, means to bring the new roll up to approximate web speed preparatoryto splicing, a retrorefiective scanner at the end of the new roll forresponse to the retrorefiective tape, and means controlled by saidscanner for so timing the operation of the splicing mechanism as tosecure registration of the preprinted matter on the expiring and newwebs when splicing.

14. A system as defined in claim 13, in which the width of theretroreective tape corresponds to the plus and minus tolerance desiredfor the splicing operation.

15. A system as defined in claim 11, in which the change in web tensionis produced by a correction signal, and in Which the scanning meansproduces a proportional error signal, and in which there is anintegrator to integrate the proportional error signal to produce anintegrated signal, and a summing amplifier to sum the proportional errorsignal and the integrated signal to thereby provide the aforesaidcorrection signal which is used for correcting the web tension.

'16. A system as defined in claim 12, in which there are additionalmeans to accelerate the response to the rapidly changing error signalcaused when the web tension is reduced to the lower limit of web tensionduring the splicing operation.

'17. A system as defined in claim 15, in which there are additionalmeans to accelerate the response to the rapidly changing error signalcaused when the web tension is reduced to the lower limit of web tensionduring the splicing operation.

18. A system as defined in claim 12, in which there is a means which isadjustable to change the timing of the splice to compensate forreduction in web tension to the lower limit of web tension.

19. A system as defined in claim 11, in which the change in web tensionis produced by a correction motor having a utilized range of motorspeed, a tachometer responsive to the web speed, and means whereby theutilized range of correction speed of the correction motor is varied inresponse to the tachometer in order to keep the same proportional to theweb speed.

20. A system as defined in claim r11, in which the transducer means is astrain gauge.

21. A system as defined in claim 11, in which there are additional meansto adjust the values of the high and low web tension limits.

22. A system as defined in claim 11, in which there are additional meansto adjust for different widths of web, so that the tension limits are inrelation to units of web length.

23. A system as defined in claim 11, in which the means operating on thepreprinted web is a printing cylinder, and in which there is additionalelectrical circuitry including a meter having a scale showing actual webtension in pounds per inch of web width and another scale showing thechange in print cylinder diameter needed for the printing cylinderoperating on the Web to establish a desired optimum web tension.

24. A system as defined in claim 9 in which said limiting means includesmeans effective to set the upper limit of web tension at a value lessthan that which would break the web.

25. A system as defined in claim 9, in which said tension limiting meansincludes means effective to set the lower limit of web tension at avalue which is high enough to prevent wandering of the web.

26. A system as defined in claim 25, which includes means for splicing anew web to an expiring web without stopping the expiring web, means toautomatically reduce the web tension to the lower limit of web tensionduring the splicing operation and until the splice leaves the system sothat it is no longer under breaking tension, and means to restore normalweb tension between the limit values and as needed for registrationafter the splice leaves the system.

27. A system as defined in claim 19 in which the tachometer develops avoltage, and in which there is apparatus to produce a variableresistance which varies in linear proportion to the said variablevoltage, said apparatus comprising a lamp, a first photoconductive meansilluminated thereby, a second photoconductive means also illuminatedthereby, an amplifier to amplify said variable voltage and to apply thesame to the lamp to excite the lamp, a feedback connection from one ofsaid photoconductive means to the amplifier, the second conductive meansbeing used as a variable resistor, the feedback from the firstphotoconductive means to the amplifier being such as to obtain avariable lamp excitation which results in a linear change in theresistance of the second photoconductive means relative to the initialinput voltage, said second photoconductive means being connected intothe control circuit of a servo motor which changes the web tensionproduced by tht.l web tension means.

28. A system as defined in claim 9, in which the means operating on thepreprinted web is a printing cylinder, and in which there is additionalelectrical circuitry including a meter having a scale showing actual webtension in pounds per inch of web width.

29. A system as defined in claim 9, in which the means operating on thepreprinted web is a printing cylinder, and in which there is additionalelectrical circuitry including a meter having a scale showing the changein print cylinder diameter needed in the printing cylinder operating onthe web to `establish a desired optimum web tension.

30. Apparatus to produce a variable resistance which varies in linearproportion to a variable voltage, said apparatus comprising a lamp, afirst photoconductive means illuminated thereby, a secondphotoconductive means also illuminated thereby, an amplifier to amplifysaid variable voltage and to apply the same to the lamp, to excite thelamp a feedback connection from one of said photoconductive means to theamplifier, the second photoconductive means being used as a variableresistor which is unconnected to the remainder of the apparatus, andwhich is therefore available for use in other circuitry, the feedbackfrom the first photoconductive means to the arnplifier being such as toobtain a variable lamp excitation which results in a linear change inthe resistance of the second photoconductive means relative to theinitial input voltage.

31. Apparatus as defined in claim 30, in which the characteristic curveof one photoconductive means showing resistance relative to lampexcitation, is matched to and is substantially the same as thecorresponding characteristic curve of the second photocell.

32. A system for handling a web, said system comprising means to measureand compare the web tension with a desired web tension and to provide aproportional tension error signal, means to integrate the proportionalerror signal to provide an integral error signal, means responsive tothe rate-of-change of the proportional error signal to provide arate-of-change signal, means to sum the proportional error signal andthe integral error signal and the rate-of-change signal to provide acorrection signal, means to vary the web tension, and a correction motorresponsive to said correction signal to appropriately adjust the saidtension varying means in that direction which helps restore the desiredweb tension.

33. A system as defined in claim 32, in which the correction motor has autilized range of motor speed, a tachometer responsive to the actual webspeed, and means whereby the utilized range of correction speed of thecorrection motor is varied in response to the tachometer in order tokeep the same generally proportional to the Web speed.

34. A system as defined in claim 33, in which the tachometer develops avoltage, and in which there is apparatus to produce a variableresistance which varies in linear proportion to the said variablevoltage, said apparatus comprising a lamp, a first photoconductive meansilluminated thereby, a second photoconductive means also illuminatedthereby, an amplifier to amplify said variable voltage and to apply thesame to the lamp to excite the lamp, a feedback connection from one ofsaid photoconductive means to the amplifier, the second conductive meansbeing used as a variable resistor, the feedback from the firstphotoconductive means to the amplifier being such as to obtain avariable lamp excitation which results in a linear change in theresistance of the second photoconductive means relative to the initialinput voltage, said photoconductive means being connected into thecontrol circuit of the said correction motor.

35. A system as defined in claim 32, in which the means to measure andcompare the Web tension includes a strain gauge applied to meanscarrying a roller engaging the web.

36. A system as defined in claim 32, in Which there are additional meansto compensate for different widths of web, so that the maintained webtension is in relation to units of web width.

37. A system as dened in claim 32, in which there is additionalelectrical circuitry including a meter having a scale showing actual webtension in units of force per unit of web width (eg. pounds per inch).

38. A system as defined in claim 32, in which there is a web feed roll,and means including differential gearspeed, and in which the correctionmotor which is reponsive to the correction signal feeds its correctioninto the said differential gearing.

References Cited UNITED STATES PATENTS 2,931,962 5/ 1960 Huck. 3,032,2455/ 1962 George et al. 3,112,052 11/1-963 Johnson.

ALLEN N. KNOWLES, Primary Examiner U.S. C1. X.R.

ing to drive the feed roll at approximately correct web 15 226-25, 30,100

